1. Field of the Invention
The present invention relates generally to friction stir welding wherein the heat necessary to create a weld is generated by plunging a rotating pin tool into the workpiece. More particularly, this invention relates to an auto-adjusting pin tool that can weld materials of varying thicknesses, and can terminate the weld joint with no voids, holes, craters or anomalies.
2. Description of Related Art
Presently pin tools for friction stir welding are of a fixed pin length, and have a disadvantage of only being able to weld materials of the same thickness, and leave a crater, or keyhole in the workpiece when the pin is retracted.
The present invention overcomes the disadvantages of the prior art devices in that the pin length is auto-adjusting and allows material of tapered thicknesses to be welded. The pin can also be incrementally retracted which eliminates the crater, or keyhole, at the weld's terminus characteristic of the prior art.
Accordingly, it is an object of the present invention to provide a new and improved auto-adjusting pin tool for friction stir welding which allows for the welding of materials of varying thicknesses without leaving a keyhole on weld termination.
Other aspects, objects and advantages of this invention will become apparent to those skilled in the art to which this invention pertains from a study of the preferred embodiment as set forth in the specifications, drawings and the appended claims.